Grinding parameters are of great concern in the success of processing good quality ceramic bearing outer rings. Practical grinding of ceramics demands appropriate parameters in respect of acceptable ceramic surfaces. In this work, a CNC grinder, MK2710, equipped with diamond grinding wheels, was used to grind ZrO<sub>2</sub> and Si<sub>3</sub>N<sub>4</sub> bearing outer rings with changing processing parameters. In order to promote the grinding quality, a series of tests were conducted to optimize the processing parameters in each process. The results showed that the outer ring surface quality has been improved and roughness (Ra) of the outer ring raceway decreased to 0.03 μm and the roundness tolerance diminished. Experiments indicated that proper grinding parameters are necessities for efficiency-processing of ceramic bearing outer rings and also help to promote grinding qualities of ceramic materials.